HART

HART is the Highway Addressible Remote Transducer

The protocol was developed by Rosemount Inc., built off the Bell 202 early communications standard, in the mid-1980s as proprietary digital communication protocol for their smart field instruments. Soon it evolved into HART. In 1986, it was made an open protocol. Since then, the capabilities of the protocol have been enhanced by successive revisions to the specification.

The HART Communications Protocol is an early implementation of fieldbus, a digital industrial automation protocol. Its most notable advantage is that it can communicate over 4-20ma analog instrumentation wiring, sharing the pair of wires used by the older system. According to Emerson,due to the huge installed base of 4-20 mA systems throughout the world, the HART Protocol was one of the most popular industrial protocols today. HART protocol made a good transition protocol for users who were comfortable using the legacy 4-20 mA signals, but wanted to implement a "smart" protocol. Industries seem to be using Foundation fieldbus more and more as users become familiar with current technology.

Smart Positioner

FEATURES

• Easy to Use – Auto Setup

The auto-setup function is a fully-automatic configuration program which
specifies the actuator and adjusts the zero and span of the valve. The
program can be turned on simply from a switch so that adjustments to the
valve can be performed quickly and safely in hazardous areas.

• Valve Diagnostic

The following parameters can be monitored by HART™ communicator or
control valve maintenance support system:

Stick slip
Cycle count
Total stroke
Shut-off count
Travel histogram
Max. travel speed

• Flexibility in Installation
  
• High Reliability .
  

Positive seating
The positive seating function completely shuts off the valve if the
input signal becomes lower than previously set. This in turn
enhances the full shut-off capabilities of the valves.


Self-diagnostic
The self-diagnostic function provides the ability to check the
status of the positioner at any time and to alert in case of failure.

• HART™ Communication
  
  HART™ communicator can be used for calibration, configuration and self-
  diagnostics.
  
• Functional Specifications
  
  Control Signal Input
  
  4-20 mA DC
  Input resistance Approx. 600 O / 20 mA DC
  (voltage between terminals 12V DC)
  
  
  Output Characteristics
  
  . Linear, equal percentage, quick opening
  . Custom user characteristics (16 points)

Make of Smart positioner

Foxboro

ABB

CCI

Fisher